The present invention relates to a new and improved construction of spinning projectile containing an electromagnetic ignition or firing current generator.
Generally speaking, the spinning projectile containing the electromagnetic ignition current generator of this development is of the type comprising a fuze housing, an inner generator component fixed at the housing and containing an armature coil or winding and an outer generator component provided with a field magnet. Further, a bearing having two bearing bodies is arranged in a recess of the fuze housing, one of the bearing bodies being arranged at the fuze housing and the other forming part of the outer generator component.
According to a state-of-the-art spinning projectile equipped with an electromagnetic ignition current generator of this type the field magnet is arrnged in a blindhole bore of the fuze housing in such a manner that it bears through the agency of a plate-shaped holder body forming one bearing body upon the base of the blindhole bore which is equipped with a sliding bearing surface forming the other bearing body. The bearing surface possesses a much smaller diameter than the field magnet. Upon passage of the projectile through the barrel of the weapon there is exerted on the one hand, upon the field magnet an axial inertia force and, on the other hand, a centrifugal force. The centrifugal force is present due to the fact that the projectile axis, owing to the play which is present between the part of the projectile body located in front of the guide band and the inner wall of the barrel, encloses a small angle with regard to the axis of the bore of the weapon barrel, and thus the center of gravity of the magnet is not located at the rotational axis of the projectile. The resultant force or resultant of the inertia force and the centrifugal force strives to tilt the field magnet about the edge of the bearing surface. This tilting moment must be counteracted by support surfaces at the fuze housing at which bears the front portion of the magnet. In this regard it is disadvantageous that there is applied to the magnet, apart from at the bearing surface, still at a further location --at the support surfaces-- sliding friction forces which exert a driving action in the direction of rotation, so that there is reduced the difference in the rotational speed between the armature coil rotating with the fuze housing and the field magnet, and which rotational speed differential is decisive for the magnitude of the generated voltage.
A further drawback of the heretofore known generator resides in the fact that the space occupied by the plate-shaped holder body is then not available for other components of the fuze.
Further, the housing wall bounding the blindhole bore must possess a certain thickness for strength considerations since it carries the entire inner generator component with the armature coil. Hence, the maximum diameter of the field magnet which is decisive for the attainable mass moment of inertia and the attainable rotational speed differential, is limited by the inner wall of the blindhole bore.